Conventionally, in a typical chair to be used in a room or in a typical vehicular seat, a cushion material or a soft pad is arranged on a part to be touched by a human body such as a seat surface and a back rest and a surface of the cushion material or the soft pad is covered with a cover-material. A variety of structures are employed for fastening the cover-material. For example, a structure capable of fastening the cover-material and concealing an outward appearance thereof has been known in which a wire is arranged in a groove of a cushion material, clips are arranged on a backside of the cover-material and the clips are engaged with the wire to thus fasten the cover-material.
For example, a fastening clip disclosed in Patent Documents 1 and 2 has a chuck part configured to be engaged to an end member for engagement, which is attached to a cover-material and a hook part configured to be engaged with a wire provided in a groove of a cushion material. The hook part has a guide lever and a hook which are arranged to face each other side by side in a lateral direction, and the wire is inserted between the guide lever and the hook, so that the guide lever is outwardly bent to widen a gap between the guide lever and the hook. When the wire is further inserted, the hook is engaged with the wire inserted into the gap.
According to the fastening clip disclosed in Patent Document 1, a lower end portion of the hook part is formed with a jig hanging part having a shape bent toward a side opposite to a part with which the wire is engaged. The jig hanging part is used to separate the fastening clip once attached from the wire. A jig such as a screwdriver is inserted into a groove shape of the bent jig hanging part and a hook material is forcibly elastically deformed outwardly, so that a gap with a guide piece is widened to separate the wire.
The cover-material fastening clip disclosed in Patent Document 2 is also formed with a jig receiving part in the middle of the hook part in a longitudinal direction. When separating the fastening clip from the wire, an operating jig is inserted into the jig receiving part and the hook is laterally deviated or inclined relative to the wire, so that the engagement between the hook and the wire is released.
Patent Document 1: Japanese Patent Application Publication No. 2012-235911A
Patent Document 2: International Patent Application Publication No. WO/2012/017986
According to the above-described related art, when separating the fastening clip, the jig is inserted in the jig hanging part and is laterally moved in parallel to be deviated or inclined relative to the wire, so that the engagement of the hook is released from the wire. However, it is difficult to know how to apply the force to the jig in order to release the engagement. In addition, it is necessary to apply the force to the jig in a correct direction, considerable skill is required to release the engagement. This is troublesome. In particular, since the jig is easily separated from the jig hanging part when the jig is upwardly pulled up, it is necessary to apply the force to the jig also in a horizontal direction while paying attention so that the jig is not separated from the jig hanging part. Thus, the operability is poor. Furthermore, when moving the jig in the horizontal direction or inclining the jig, the cushion material around the jig becomes an obstacle, so that it is necessary to push and deform the cushion material to move the jig. Also from this standpoint, the strong force is required, it takes time to perform the operation and the fatigue of an operator is increased.